Understanding and manipulating lignin biosynthesis in barley

植物产生木质素的途径在双子叶植物(烟草、拟南芥和杨树)中已经得到了广泛的研究，但对禾本科植物的这一途径知之甚少。禾本科植物的细胞壁和木质素有几个独特的特征，这是研究双子叶植物无法理解的。我们想要研究直接在一种经济上重要的草--大麦中制造木质素的基因。我们将能够非常容易地识别大多数基因，因为它们很可能与拟南芥中已经识别的基因非常相似。然而，几个新的基因可能对草很重要，特别是那些涉及产生使草细胞壁独特的特征的基因。我们预计，这些基因将与已知的木质素基因在同一时间和同一位置被激活，这给了我们一个识别它们的把柄。对于每个已知的或新的基因，我们想要确定它在制造木质素方面的功能，以及没有该基因的植物是否对农业或工业有任何优势。例如，草中木质素的含量会影响喂食该草的动物消化它的难度，因为木质素本身相当难消化，它包围着植物细胞壁中其他更容易消化的成分。玉米植株中涉及制造木质素的特定基因已经被敲除或通过突变降低了效率，玉米植株的木质素含量减少，比正常玉米植株更容易消化。我们希望通过鉴定和研究大麦中产生木质素的基因的突变来了解大麦中是否也存在这种情况。这项工作不仅教会了我们更多关于植物细胞壁是如何在草中形成的知识，还可能为如何改良大麦作物带来新的想法。事实上，在这项工作中发现的有用的突变可以直接纳入大麦育种计划。

The pathway whereby plants make lignin, a strengthening and waterproofing substance in cell walls, has been extensively studied in dicot plants (tobacco, Arabidopsis and poplar) but little is known about the pathway in grasses. Cell walls and lignin in grasses have several unique features that cannot be understood by studying dicots. We want to study the genes that are involved in making lignin directly in an economically-important grass, barley. We will be able to identify most of the genes quite easily as they are likely to be very similar to the genes already identified in Arabidopsis. However several novel genes may be important in grasses, particularly those involved in generating the features that make grass cell walls unique. We expect that these genes will be switched on at the same time and in the same place as the known lignin genes giving us a handle with which to identify them. For each known or novel gene, we want to determine the function it has in making lignin and whether plants without that gene have any advantages for agriculture or industry. For example, the amount of lignin in a grass influences how difficult it is for animals who are fed that grass to digest it, as lignin itself is fairly indigestible and it surrounds the other, more digestible, components of plant cell walls. Maize plants where specific genes involved in making lignin have been 'knocked-out' or made less efficient through mutation, have reduced amounts of lignin and are more digestible than normal counterparts. We want to see if this is true also in barley by identifying and studying barley mutants in the genes that make lignin. As well as teaching us more about how plant cell walls are made in grasses, this work may lead to new ideas about how to improve the barley crop. In fact, useful mutants identified in the course of this work could be directly incorporated into barley breeding programmes.